(1) Field of the Invention
The present invention relates to the manufacture of books. More particularly, the present invention relates to the manufacture of sewn books.
(2) Description of the Prior Art
In the manufacture of books, two basic methods of book production have found acceptance: thread stitching of books and flexible binding of books. Both methods have conventional fields of application. The thread stitching method is typically used for the production of high quality books as well as reference books which are heavily stressed during use, that is, typically non-fiction books such as atlases, dictionaries and the like. The method of flexible binding is typically used in the making of inexpensive books such as telephone directories, catalogs and pocket books. Typically, the flexible binding method is used to manufacture books that are not stressed heavily during use.
Generally speaking, it is desirable to manufacture books by the thread stitching method since a book manufactured by the thread stitching method is more durable than one produced by the flexible binding method. However, the flexible binding method is often used instead of the thread stitching method because the thread stitching method is relatively expensive. Thus, the flexible binding method is useful particularly in the bulk production of novels. The novels must have the external presentation of a quality book but since there are no great requirements for its durability, the books are typically made by the flexible binding method. Thus, the heavy reliance on the flexible binding method for the production of books is due at least in part, to the expense of the conventional thread stitching method.
The conventional thread stitching method is carried on in such a manner that the processing speed of the book layers or signatures to form a sewn book is particularly low in comparison to the speed of other processing steps required to form a finished book. Restated, the conventional stitching phase of manufacturing method is much more time consuming than other phases of the manufacturing method such as back rounding, back lining, head banding and case working, the efficiency of which has been considerably improved. Thus, the difference in the processing speed of the stitching of the book layers together and the other steps in the manufacture of the books is enlarged. Because of the speed differential, the layers of the book must be sewn together and the sewn book must be stored and palletized prior to other phases of the manufacturing method.
It is an object of the invention to provide an efficient and economical apparatus for and method of thread stitching of layers or signatures to form a sewn book. Other objects will be apparent from the following description.